Index: aclocal/Makefile
==================================================================
--- aclocal/Makefile
+++ aclocal/Makefile
@@ -1,2 +1,2 @@
-../aclocal.m4: acx_pthread.m4 dc_shobjs.m4 dc_pcscheaders.m4
+../aclocal.m4: acx_pthread.m4 dc_shobjs.m4 dc_pcscheaders.m4 dc_versionscript.m4
 	cat $^ > "$@"

Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -75,14 +75,17 @@
 dnl Check for PC/SC headers and libraries
 DC_PCSC
 
 dnl Check for ZLIB libraries
 AC_CHECK_LIB(z, uncompress)
+
+dnl Set version script, to limit the scope of symbols
+DC_SETVERSIONSCRIPT(libcackey.vers)
 
 dnl Upate LDFLAGS to include setting the run-time linker path to the same as our compile-time linker
 DC_SYNC_RPATH
 
 dnl If we updated LIBOBJS, update SHLIBOBJS -- must be last.
 DC_SYNC_SHLIBOBJS
 
 dnl Produce Makefile
 AC_OUTPUT(Makefile)

ADDED   libcackey.vers
Index: libcackey.vers
==================================================================
--- libcackey.vers
+++ libcackey.vers
@@ -0,0 +1,73 @@
+{
+	global:
+		C_CancelFunction;
+		C_CloseAllSessions;
+		C_CloseSession;
+		C_CopyObject;
+		C_CreateObject;
+		C_Decrypt;
+		C_DecryptDigestUpdate;
+		C_DecryptFinal;
+		C_DecryptInit;
+		C_DecryptUpdate;
+		C_DecryptVerifyUpdate;
+		C_DeriveKey;
+		C_DestroyObject;
+		C_Digest;
+		C_DigestEncryptUpdate;
+		C_DigestFinal;
+		C_DigestInit;
+		C_DigestKey;
+		C_DigestUpdate;
+		C_Encrypt;
+		C_EncryptFinal;
+		C_EncryptInit;
+		C_EncryptUpdate;
+		C_Finalize;
+		C_FindObjects;
+		C_FindObjectsFinal;
+		C_FindObjectsInit;
+		C_GenerateKey;
+		C_GenerateKeyPair;
+		C_GenerateRandom;
+		C_GetAttributeValue;
+		C_GetFunctionList;
+		C_GetFunctionStatus;
+		C_GetInfo;
+		C_GetMechanismInfo;
+		C_GetMechanismList;
+		C_GetObjectSize;
+		C_GetOperationState;
+		C_GetSessionInfo;
+		C_GetSlotInfo;
+		C_GetSlotList;
+		C_GetTokenInfo;
+		C_InitPIN;
+		C_InitToken;
+		C_Initialize;
+		C_Login;
+		C_Logout;
+		C_OpenSession;
+		C_SeedRandom;
+		C_SetAttributeValue;
+		C_SetOperationState;
+		C_SetPIN;
+		C_Sign;
+		C_SignEncryptUpdate;
+		C_SignFinal;
+		C_SignInit;
+		C_SignRecover;
+		C_SignRecoverInit;
+		C_SignUpdate;
+		C_UnwrapKey;
+		C_Verify;
+		C_VerifyFinal;
+		C_VerifyInit;
+		C_VerifyRecover;
+		C_VerifyRecoverInit;
+		C_VerifyUpdate;
+		C_WaitForSlotEvent;
+		C_WrapKey;
+	local:
+		*;
+};